本研究记述粤西云开地区中奥陶统东冲组一种奇异的翼形类(双壳类)化石, 建立了郁南蛤超科(新超科) Yunannioidea (superfam. nov.), 郁南蛤科(新科) Yunanniidae (fam. nov.), 郁南蛤属(新属) Yunannia (gen. nov.)及 2 新种: 干坑郁南蛤(新属新种) Yunannia gankengensis (gen. et sp. nov.)和云开郁南蛤(新属新种) Yunannia yunkaiensis (gen. et sp. nov.)。讨论了它们的内部构造特征及分类位置。
The Ordovician in Yunkai area of western Guangdong Province mainly consists of sandstone, pelitic siltstone, silty mudstone and pebbly sandstone, and mudstone with intercalated carbonate rock lenses and conglomerates. The Ordovician includes the Lower Ordovician Luohong Formation and Luodong Formation, Middle Ordovician Dongchong Formation, and Upper Ordovician Lanweng Formation. Fossil bivalves, including the new taxa described in this paper, were collected from an about 2-meter-thick bed of gray to grayish yellow silty mudstone and pelitic siltstone of the upper part of the Dongchong Formation. The collection includes about one thousand bivalve specimens, which represent more than 22 species of16 and several unnamed genera and may be a new taxon. We report a group of unique bivalves including two new species of Yunannia (gen. nov.) of a new Family Yunanniidae Zhang et Niu and a new Superfamily Yunannioidea Zhang et Niu. This group demonstrate combined features normally attributed to different bivalve taxa. A small number of trilobites, including Nileus sp., Lonchobasilicus sp., Calymenesun tingi (Sun), Calymenesun sp., Asaphopsis? sp., and brachiopods, including Paralenorthis sp., Aegira sp., Leptellina sp., Obolus? sp., Strophomena sp. and Nicolella sp., cooccur with the bivalves and indicate the Middle Ordovician age.